1. Field of the Invention
This invention relates to a device for absorbing variation in a rotating force or torque to transmit it smoothly from a driving shaft, such as the output shaft of an automobile engine, to a driven shaft.
2. Description of the Prior Art
Devices of the type to which this invention pertains are disclosed in, for example, Japanese Laid-Open Patent Specification No. 57739/1980 and Japanese Patent Application No. 174452/1984. These devices are effective at a practical rotating speed of e.g. an engine if their own natural frequency is allowed to stay below the practical rotating speed (or idling speed) of the engine. This, however, requires the provision of play having a certain angle to obtain a wide angle of torsion.
The damper mechanism which any such known device includes can produce only a limited angle of torsion. It is, therefore, necessary to provide a first stage of play having a by far greater angle than is normally required.
If the play has a great angle, however, the ON-OFF operation of an accelerator at a torque of about 0 kgm results in a rattling differential or a sobbing vehicle. A large magnitude of hysteresis is preferred to absorb any such rattling or sobbing. On the other hand, a small magnitude of hysteresis is preferred to absorb fine vibration which occurs when the engine is idling, or fine vibration which occurs when the vehicle is slowly accelerated.